Compounds of the formula ##STR2## wherein R.sub.1 and R.sub.2 are each independently hydrogen, alkyl, cycloalkyl or R.sub.1 and R.sub.2 together with the carbon atom form a 3 to 6 member cycloalkyl group, or aryl are important intermediates in the preparation of beta-agonists and antagonists. The compound L-solketal ##STR3## is a particularly important intermediate for preparing optically active beta-agonists and antagonists and a chiral building block in a number of natural products. Lok et al in Chemistry and Physics of Lipids, 16 (1976), 115-122, describes the synthesis of chiral glycerides starting from D- and L-serine and at page 118 describes the preparation of solketal, 2,3-O-isopropylidene-sn-glycerol.
However, the process described requires the use of large amounts of water, an extensive working period of several days, and low processing temperatures. It thus does not lend itself to the large scale production of the noted compounds. In particular, the large quantity of water which is required in relation to the quantity of reactants makes the process inappropriate for large scale production. Furthermore, when attempting to repeat the method of the prior art with the modification of reducing the amount of water by one-half, c.a. 1.5 liters instead of 3 liters of water, it was found that the optical rotation of the final product, solketal, was only -9.57 (Neat) instead of -13.2 (Neat). This is believed to be due to partial isomerization in higher concentration of hydrochloric acid.